<script>
  var url = document.location.href;
  var imageUrl = url.replace(/[/][^/]*$/, "/blue-circle-16x16.png");
  var viewSourceImageUrl = "view-source:" + imageUrl;
  var html = "<iframe src='#url#'></iframe>".replace(/#url#/, viewSourceImageUrl);
  document.write(html);
</script>

